The Following Is Part of the Results of a Regression

Essay

The following is part of the results of a regression analysis involving sales (y in millions of dollars), advertising expenditures (x₁ in thousands of dollars), and number of salespeople (x₂) for a corporation.The regression was performed on a sample of 10 observations. $$\begin{array} { c l l } & \text { Coefficients } & \text { Standard Error } \\\text { Intercept } & 40.00 & 7.00 \\\mathrm { x } _ { 1 } & 8.00 & 2.50 \\\mathrm { x } _ { 2 } & 6.00 & 3.00\end{array}$$ ​
a.
If the company uses $40,000 in advertisement and has 30 salespeople, what are the expected sales? Give your answer in dollars.
b.
At α = .05, test for the significance of the coefficient of advertising.
c.
At α = .05, test for the significance of the coefficient of the number of salespeople.